Hoisting, Rigging, Sling Inspection, and Load Control

Hoisting, Rigging, Sling Inspection, and Load Control

Rigging is the connection between the lifting equipment and the load, and small errors produce large failures. The governing construction standard is 29 CFR 1926.251, Rigging equipment for material handling, which requires that rigging be inspected before each shift and as needed during use, and that defective gear be removed from service. The CHST need not be the qualified rigger for every lift, but must recognize when the lift plan, gear condition, or work-area control is unacceptable.

Start With the Load

Before choosing rigging, determine the load weight, shape, center of gravity (CG), lift points, sharp edges, stability, and landing method. Use drawings, shipping papers, manufacturer markings, or scale tickets — guessing is not a plan. The CG matters because a load lifted off its balance point will tilt, roll, or shift suddenly. The hook should sit directly above the CG so the load lifts level.

The load path must be clear from pickup to landing. The landing area must be strong, level, and prepared with cribbing or dunnage where needed. Workers keep hands out from under the load and never place themselves between the load and a fixed object.

Sling Angle Is a Top Exam Topic

The sling angle (measured from horizontal) multiplies the tension in each leg. As the angle decreases, tension climbs even though the load weight is unchanged — a frequent trap question. Maintain angles above 30 degrees from horizontal whenever possible; many programs set 45 to 60 degrees as the working minimum.

Worked example: a 4,000 lb load on a two-leg bridle splits to 2,000 lb per leg in a true vertical pull. At a 30-degree angle each leg now carries 2,000 x 2.0 = 4,000 lb — so a 5,000 lb-rated sling that looked safe at 90 degrees can be overloaded. Correct it with longer slings, a spreader bar, or repositioned lift points.

Sling and Hardware Rejection Criteria

Tag and remove damaged rigging so it cannot be reused — leaving bad gear in the gang box invites later use under schedule pressure. A missing identification tag alone is a removal condition because the working load limit (WLL) can no longer be verified.

Hitch Type, Edges, and Load Control

A vertical hitch gives full rated capacity; a choker hitch reduces capacity (commonly to about 75-80 percent because of the bend at the choke point); a basket hitch can roughly double capacity only if the legs stay vertical and the load cannot slide out. Sharp edges require corner protection or pads, because a 90-degree edge can slice a synthetic sling or sharply reduce wire-rope strength. On multi-leg bridle lifts with a rigid load, do not assume the legs share equally — two legs may carry the entire load while the others only steady it.

Control movement: keep the load low during the initial test lift, pause to confirm balance, and avoid sudden starts and stops. Tag lines may control rotation, but the worker stands clear of the fall zone and never wraps the line around a hand, body, or fixed object. If a tag line creates a trip, fall, or entanglement hazard, use a different control.

Communication and the Exam

Only the designated signal person directs hoist movement — except that anyone may give an emergency stop. The operator does not move on unclear, conflicting, or casual signals. For CHST scenarios, choose the answer that verifies capacity, condition, configuration, and control. Do not accept damaged rigging, unknown load weight, workers under the load, or informal signaling; the right field action is often to pause the lift, get qualified rigging input, replace defective gear, or revise the method.

Design Factors and Qualified vs Competent

Know the vocabulary the exam tests. Slings carry a design factor (sometimes called safety factor) typically of 5 to 1 for new slings, meaning a sling rated at 2,000 lb working load limit was tested to roughly 10,000 lb breaking strength — but that margin is consumed by wear, shock loading, and shallow angles, so it is not a license to overload. A qualified rigger has a recognized degree, certificate, or extensive knowledge and training to solve rigging problems; a competent person can identify hazards and has authority to correct them.

Subpart CC requires a qualified rigger for assembly/disassembly work and for hoisting personnel. Shock loading — jerking the load or a sudden stop — can multiply the force in the rigging well beyond the static load and is a frequent root cause of sling and hardware failure.